In the film, to touch the Ark is to die, but at the end of the film King David touches the Ark and lives which means that his sins (with Bathsheba) have been forgiven.

Interesting. While it's certainly Biblical that King David's sins with Bathsheba were forgiven, as 2 Samuel 12:1-15 indicates when God used Nathan the prophet to bring His judgment to David as well as His forgiveness when David repented- however, the part about David touching the Ark of the Covenant is not in The Bible. It's an interesting symbolic touch (no pun intended ), but yes- touching the Ark brought death because it went against God's command. His holy presence dwelt in the Ark and He cannot have sin in His presence. That's why He sent Christ to permanently pay for all sin through His death and Resurrection. Now those who put faith in Him don't have to carry around the Ark of the Covenant and try to use it as a "radio for speaking to God" but can instead talk directly to Him. (1 Timothy 2:5-6)